1. Field of the Invention
The invention relates to a shaft for flexible technical and surgical endoscopes which at least partly comprises circular braiding of webs interwoven with one another.
2. Description of the Prior Art
In known shafts of this type, the webs or layers of the braiding consist of circular wires which run parallel or are interwoven to form braidings. The braiding machine must be fitted with a number of wire coils corresponding to the number of wires, with corresponding complexity, because of the plurality of wires required for constructing such circular braiding. In addition, in the conventional method of braiding using circular wires, it is not possible to achieve a low wall thickness, since even for a parallel arrangement of the wires belonging to a web, the bending radii thereof are relatively large in the region of the crisscrosses. This disadvantage can also be detected particularly in circular braidings, the webs of which are braidings or flat braidings.
Finally, braidings produced from circular wires are unstable and have low torsion resistance. This applies particularly also if braiding of the webs is additionally carried out to be double-braided or polybraided, hence for example the braiding is `2 over 2`, in which one web after the other in each case runs initially over two and then below two webs crossing them. When using braidings of this type for endoscope shafts, mechanical stabilisation is therefore usually required which consists of a flat wire helix lying on the inside in most cases and supporting the braiding from the inside.
The object of the invention consists in providing an endoscope shaft having a circular braiding which is simple to manufacture and which is dimensionally stable and torsion resistant in spite of low wall thickness, but otherwise has adequate flexibility.